Hearing aid device comprising a sensor member

ABSTRACT

A hearing aid device is disclosed. The hearing aid device comprises means to improve, augment and/or protect the hearing capability of a user by receiving acoustic signals from the surroundings of the user, generating corresponding audio signals, possibly modifying the audio signals and providing the possibly modified audio signals as audible signals to at least one of the user&#39;s ears. The hearing aid device comprises a sensor member for detecting the movement and/or acceleration and/or orientation (or spatial position) of the hearing aid device. The hearing aid device comprises at least two hearing aid microphones and a control unit for determining the position or a deviation from an intended position of the hearing aid device or hearing aid microphones. The hearing aid device is configured to compensate for a possible dislocation of the hearing aid microphones.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of co-pending U.S. Ser. No. 16/678,567,filed Nov. 8, 2019, which is a Divisional of U.S. application Ser. No.15/790,523, filed on Oct. 23, 2017 (now U.S. Pat. No. 10,524,061 issuedon Dec. 31, 2019), which is a Divisional of U.S. application Ser. No.15/420,268, filed on Jan. 31, 2017 (now U.S. Pat. No. 9,826,318 issuedon Nov. 21, 2017), which is a Divisional of U.S. patent application Ser.No. 14/620,685, filed on Feb. 12, 2015 (now U.S. Pat. No. 9,596,551issued on Mar. 14, 2017), which claims the benefit of European PatentApplication No. 14155022.8, filed on Feb. 13, 2014. The entire contentsof which are hereby incorporated by reference.

FIELD OF INVENTION

The present disclosure generally relates to a hearing aid devicecomprising a sensor member. The disclosure more particularly relates toa hearing aid device comprising a sensor member for detecting themovement and/or acceleration and/or orientation (or spatial position) ofthe hearing aid device. The disclosure also relates to a hearing aidsystem comprising a) two hearing aid devices and/or b) at least onehearing aid device and an auxiliary device the hearing aid device(s)comprising a sensor member for detecting the movement and/oracceleration and/or orientation (or spatial position) of the hearing aiddevice.

PRIOR ART

In the field of hearing aid devices there is an increasing awarenesstowards individual adaptation of the hearing aid settings in order toprovide wearers with an optimum sound experience. All hearing aidproducers aim for providing hearing aid devices that are capable oflearning the wearer's individual preferences so that the hearing aiddevices can deliver a just-right sound amplification.

Such optimization may be carried out by fitting the hearing aid deviceon the basis of a number of individual parameters, however, someparameters are difficult to access and quantify. Parameters such as thelevel of physical activity and the head movement of the user of thehearing aid device may be of great importance.

Movement sensors and compasses are increasingly built into portableelectronic devices, e.g. mobile telephones, tablet computers, cameras,etc., e.g. to adapt a screen image to a current orientation of thedevice in question. Several uses of such sensors in hearing aid deviceshave likewise been proposed.

U.S. Pat. No. 6,330,339 describes e.g. a hearing aid wherein outputs ofa pulse sensor, a brain wave sensor, a conductivity sensor and anacceleration sensor are input to respectively corresponding conditiondetecting means, and the condition of the wearer (biologicalinformation, motion) is detected by the condition detecting means.EP1530402B1 describes e.g. a hearing aid having a plurality ofmicrophones for recording input signals and a computing device forcalculating at least one direction from which a predefined acousticsignal comes in, on the basis of the input signals and a positiondetermining device for determining the current position of the head ofthe hearing aid wearer, so that with the aid of the position of the headthe direction to be calculated in the calculating unit can beinfluenced.

SUMMARY OF THE INVENTION

Thus, it would be advantageous to be able to continuously andautomatically have access to information about the level of physicalactivity of the user of the hearing aid device. Accordingly, it is anobject of the present disclosure to provide a hearing aid device that isable to continuously and automatically provide information about thelevel of physical activity and the head movement of the user of thehearing aid device.

It would also be an advantage to have information about the orientationof the hearing aid device (e.g. relative to another device or to areference direction), since such information may be used to optimise anoise reduction (e.g. including a directional) system of a hearing aiddevice. Therefore, it is an object of the present disclosure to providea hearing aid device that is able to automatically provide informationabout the orientation of the hearing aid device.

Is an object of the present disclosure to provide a hearing aid devicethat is able to detect if the hearing aid user is moving or turning hishead.

Is an object of the present disclosure to provide a hearing aid devicethat is capable of preventing the hearing aid from being lost.

It is also an object of the present disclosure to provide a hearing aidsystem capable of determining the orientation of a pair of hearing aiddevices relative to each other.

A lot of applications can be envisioned, if a movement sensor (e.g. anacceleration sensor and/or a gyroscope) and/or a compass is built into ahearing aid device. It may e.g. be controlled by head movements, e.g. anod or rotation of the head to a side, or a combination thereof. Suchsensors can e.g. be used to control details of a directionalityalgorithm, to provide that a ‘look direction’ of a microphone systemfollows the head movement. This and other applications the use of suchsensors in hearing aid devices are topics of the present application.

Objects of the present disclosure can be achieved by a hearing aiddevice as defined in claim 1 and by a hearing aid system as defined inclaim 17. Preferred embodiments are defined in the dependent sub claimsand explained in the following description and illustrated in theaccompanying drawings.

The hearing aid device according to the disclosure is a hearing aiddevice comprising means to improve, augment and/or protect the hearingcapability of a user by receiving acoustic signals from the surroundingsof the user, generating corresponding audio signals, possibly modifyingthe audio signals and providing the possibly modified audio signals asaudible signals to at least one of the user's ears. The hearing aiddevice comprises a sensor member for detecting the movement and/oracceleration of the hearing aid device.

This information can be used to continuously and automatically provideinformation about the level of physical activity of the user of thehearing aid device. The hearing aid device can also provide informationabout the orientation of the hearing aid device and detect if thehearing aid user is moving or turning his head.

The sensor may be any suitable type of sensor capable of detectingmovement and/or acceleration and/or orientation and/or position of thehearing aid device.

The sensor may be an integrated part of the hearing aid device or beattached to the hearing aid device in any suitable way.

The term “movement and/or acceleration” includes both linear and angularposition, velocity and acceleration. Thus, “movement and/oracceleration” may include position, orientation as well as the first andsecond derivative (e.g. with respect to time) of these. The term“orientation” may e.g. indicate a direction in a stationary coordinatesystem relative to the earth, or relative to a reference direction, e.g.a direction of the force of gravity, on a particular location on (thesurface of) the earth. A “position” of a device may e.g. indicate a setof coordinates in a stationary coordinate system relative to the earth,e.g. the surface of the earth (e.g. GPS-coordinates). These quantitiesmay be expressed in any coordinate system and by means of any unit e.g.the International System of Units (SI).

In the present context, a “hearing aid device” refers to a device, suchas e.g. a hearing aid, a listening device or an active ear-protectiondevice, which is adapted to improve, augment and/or protect the hearingcapability of a user by receiving acoustic signals from the user'ssurroundings, generating corresponding audio signals, possibly modifyingthe audio signals and providing the possibly modified audio signals asaudible signals to at least one of the user's ears.

A “hearing aid device” may further refer to a device such as an earphoneor a headset adapted to receive audio signals electronically, possiblymodifying the audio signals and providing the possibly modified audiosignals as audible signals to at least one of the user's ears. Suchaudible signals may e.g. be provided in the form of acoustic signalsradiated into the user's outer ears, acoustic signals transferred asmechanical vibrations to the user's inner ears through the bonestructure of the user's head and/or through parts of the middle ear aswell as electric signals transferred directly or indirectly to thecochlear nerve and/or to the auditory cortex of the user.

A hearing aid device may be configured to be worn in any known way, e.g.as a unit arranged behind the ear with a tube leading air-borne acousticsignals into the ear canal or with a loudspeaker arranged close to or inthe ear canal, as a unit entirely or partly arranged in the pinna and/orin the ear canal, as a unit attached to a fixture implanted into theskull bone, as an entirely or partly implanted unit, etc. A hearing aiddevice may comprise a single unit or several units communicatingelectronically with each other.

More generally, a hearing aid device comprises an input transducer forreceiving an acoustic signal from a user's surroundings and providing acorresponding input audio signal and/or a receiver for electronicallyreceiving an input audio signal, a signal processing circuit forprocessing the input audio signal and an output means for providing anaudible signal to the user in dependence on the processed audio signal.

Some hearing aid devices may comprise multiple input transducers, e.g.for providing direction-dependent audio signal processing. In somehearing aid devices, the receiver may be a wireless receiver. In somehearing aid devices, the receiver may be e.g. an input amplifier forreceiving a wired signal. In some hearing aid devices, an amplifier mayconstitute the signal processing circuit. In some hearing aid devices,the output means may comprise an output transducer, such as e.g. aloudspeaker for providing an air-borne acoustic signal or a vibrator forproviding a structure-borne or liquid-borne acoustic signal. In somehearing aid devices, the output means may comprise one or more outputelectrodes for providing electric signals.

In some hearing aid devices, the vibrator may be adapted to provide astructure-borne acoustic signal transcutaneously or percutaneously tothe skull bone. In some hearing aid devices, the vibrator may beimplanted in the middle ear and/or in the inner ear. In some hearing aiddevices, the vibrator may be adapted to provide a structure-borneacoustic signal to a middle-ear bone and/or to the cochlea. In somehearing aid devices, the vibrator may be adapted to provide aliquid-borne acoustic signal in the cochlear liquid, e.g. through theoval window. In some hearing aid devices, the output electrodes may beimplanted in the cochlea or on the inside of the skull bone and may beadapted to provide the electric signals to the hair cells of thecochlea, to one or more hearing nerves and/or to the auditory cortex.

A “hearing system” refers to a system comprising one or two hearing aiddevices, and a “binaural hearing system” refers to a system comprisingone or two hearing aid devices and being adapted to cooperativelyprovide audible signals to both of the user's ears. Hearing systems orbinaural hearing systems may further comprise “auxiliary devices”, whichcommunicate with the hearing aid devices and affect and/or benefit fromthe function of the hearing aid devices. Auxiliary devices may be e.g.remote controls, remote microphones, audio gateway devices, mobilephones, public-address systems, car audio systems or music players.Hearing aid devices, hearing systems or binaural hearing systems maye.g. be used for compensating for a hearing-impaired person's loss ofhearing capability, augmenting or protecting a normal-hearing person'shearing capability and/or conveying electronic audio signals to aperson.

In an aspect, a hearing aid device for improving, augmenting and/orprotecting the hearing capability of a user when receiving acousticsignals from the surroundings of the user is provided. The hearing aiddevice comprises an input unit for generating corresponding audiosignals, a signal processing unit for modifying the audio signals, andan output unit for providing modified audio signals as audible signalsto at least one of the user's ears. The hearing aid device furthercomprises a sensor member for detecting the movement and/or accelerationan/or orientation and/or position of the hearing aid device. The hearingaid device comprises at least two hearing aid microphones and a controlunit for determining the position or a deviation from an intendedposition of the hearing aid device or the hearing aid microphones. Thehearing aid device is configured to compensate for a possibledislocation of the hearing aid microphones.

The hearing aid device may be any type of hearing aid device including abehind-the-ear (BTE) hearing aid, an in-the-ear (ITE) hearing aid, acompletely-in-canal (CIC) hearing aid, an in-the-canal (ITC) hearingaid, a receiver-in-the-ear (RITE) hearing aid. In an embodiment, thehearing aid device comprises a BTE part (adapted for being locatedbehind or at an era of a user) operationally connected to a loudspeaker(receiver) and a microphone located in an ear canal of the user.

It may be beneficial that the sensor member is or comprises anaccelerometer and/or a gyroscope. In an embodiment, the sensor member isor comprises a compass, e.g. a magnetic compass, e.g. a magnetometer. Inan embodiment, the sensor member is or comprises a positioning system(e.g. a receiver of a satellite positioning system, e.g. a GPSreceiver). Hereby, it is possible to use robust and reliable standardcomponents to detect the desired data.

The accelerometer may be an accelerometer configured to measure linearacceleration in one, two or three directions, whereas the gyroscope maybe a gyroscope configured to measure angular velocity in one, two orthree directions. A compass preferably indicates a direction in ahorizontal plane at a particular place on the surface of the earth, e.g.in a North, West, South, East framework.

It may be an advantage that the hearing aid device contains both anaccelerometer and a gyroscope so that both linear and rotationalmovement of the head of the user or of the hearing aid can be determinedwith high precision and accuracy. In an embodiment, the hearing aiddevice (or a device in communication with the hearing aid device)additionally comprises a positioning system and/or a compass.

Both accelerometers and gyroscopes are as components designed withspecific x, y and z axis relative to their housing. Designing thesensors into hearing aids can be done in ways where the axis oforientations of the sensors directly matches the axis of orientations ofthe hearing aids (e.g. an axis defined by a ‘direction of microphones’)when they are placed on a person's ears. In this way no conversion ofthe accelerometer data is needed to achieve correct movement data (i.e.moving forward may e.g. correspond directly to the positive direction ofthe accelerometers x-axis). Alternatively, a fixed transformation of thedata can be carried out by use of fixed spatial rotation of the axis,based on previous calculated placement of the sensors in the usersituation relative to a characteristic direction of the hearing aiddevice (e.g. a direction defined by the housing of the hearing aiddevice, e.g. a an outer edge of the housing). But to allow userindividualization as well as allowing for free orientation of thesensors, it is advantageous to detect the sensors' placement relative tothe head of the user by detecting movement data for each hearing aiddevice and to compare such data between the hearing aid devices. Aspatial rotation matrix may be determined from the combined data, andthis can be used for spatial transformation of the sensors' axis to theusers current head orientation. The transformation should preferably becontinuously adapting to the user's head movements.

It may be an advantage that the hearing aid device comprises means fordetecting the level of physical activity of the hearing aid user.

Hereby it is possible to provide a more optimal adjustment of thesettings of the hearing aid device. It is possible to have a hearing aiddevice, in which the hearing aid device settings change automaticallywhile the user is wearing and using the hearing aid device. The settingsmay be controlled on the basis of measurements made by the sensormember. This may be done in combination with simultaneous application ofother detectors (sensor members). In this way it is possible to changesettings when environment parameters change or when the level ofphysical activity of the hearing aid user wearing the hearing aid devicechanges. Thus, the hearing aid device automatically selects the mostoptimal settings based on the detected level of physical activity of thehearing aid user.

It may be an advantage that the hearing aid device comprises means forlogging and storing data representing the level of physical activity ofthe hearing aid user.

It may be an advantageous that the hearing aid device comprises meansfor providing communication with an external device (e.g. a mobile phonehaving means for logging and storing data representing the level ofphysical activity of the hearing aid user).

It may be beneficial that the hearing aid device comprises means forsetting the compression system of the hearing aid device and/or thenoise reduction system on the basis of measurements provided by means ofthe sensor member. Hereby the hearing aid device can provide the wearerof the hearing aid device with an optimum sound experience.

It may be an advantage that the hearing aid device comprises means forsetting the speed of the compression system and/or the aggressiveness ofthe noise reduction system on the basis of information about the levelof physical activity of the hearing aid user provided by means of thesensor member. Hereby it is possible to provide a hearing aid devicethat is capable of learning the wearer's individual preferences and thusis capable of delivering an optimum sound amplification and soundexperience.

It may be advantageous that the hearing aid device user wears orotherwise is in contact with means for applying actual measurements ofthe level of physical activity as well as prior knowledge about theuser's individual behaviour (e.g. on the basis of logged data) tooptimise the hearing aid device settings on an individual basis.

It may be an advantage that the hearing aid device comprises means forproviding a number of predefined settings each corresponding tocorresponding levels of physical activity of the hearing aid usermeasured on a predefined scale.

It may be beneficial that the hearing aid device comprises means forproviding predefined settings (such as fast time constants in thecompression system or a more “aggressive” setting for the noisereduction) when the hearing aid device detects that the hearing aid useris physically active measured on a predefined scale.

It may be an advantage that the hearing aid device comprises means forproviding other (e.g. less “aggressive”) settings when the hearing aiddevice detects that the hearing aid user is physically less activemeasured on a predefined scale.

It may be beneficial that the hearing aid device comprises means forchanging the settings of the hearing aid device over time based onmeasurements provided by means of the sensor member. Hereby it isachieved that the hearing aid device constantly can provide the mostoptimal sound experience for the user. The most optimal settings can beapplied by constantly changing the settings on the basis of measurementsprovided by means of the sensor member.

It may be advantageous that the hearing aid device comprises means forchanging the settings with a predefined speed over time based on thedifferent input, including the level of physical activity detected bymeans of the hearing aid device.

It may be an advantage that the hearing aid device comprises anaccelerometer and/or a gyroscope that is built-in or integrated into thehearing aid device and that the hearing aid device is configured to beused as part of a fitting tool, where e.g. the activity level of thehearing aid user is combined with measurements of the environmentprovided by the hearing aid device or by another device (e.g. a mobilephone), e.g. in a situation where this information define preferences ofthe user of the hearing aid device. This may be done (e.g.automatically) while switching between different hearing aid deviceprograms corresponding to different levels of activity or by changingthe settings in a hearing aid device with a remote control or with amobile phone.

It may be an advantage that the hearing aid device comprises means forrepeating a number of predefined measurements by means of the sensormember and that the hearing aid device comprises means for automaticallyadjust to the user's preferences determined on the basis of thepredefined measurements. When such predefined measurements have beencarried out in similar environments for a period of time (e.g. fewweeks) the hearing aid device settings may be able to automaticallyadjust to the user's preferences and thus provide an optimum soundexperience for the hearing aid user.

It may be beneficial that the hearing aid device comprises means forlogging different user preferences in the hearing aid device. Hereby,individual preferences may be further used in the development, where thepreferred settings may be logged and used to find optimal settings forother similar users in similar environments.

It may be beneficial that the hearing aid device comprises means forcollecting these user preferences in a network (e.g. stored at aserver).

It may be beneficial that the hearing aid device comprises means fordetecting if the hearing aid user is moving or turning the head, wherethe hearing aid device comprises means for improving and/or augmentingreceived acoustic signals from the surroundings of the hearing aid userby compensating for the head movement if it is detected that the hearingaid user is moving or turning the head. Hereby, when a head movement isdetected, the spatial perception of an artificial sound or any soundwhich is not directly picked up by the hearing aid microphones may beimproved by compensating for the head movement.

It may be advantageous that the hearing aid device comprises two hearingaid microphones and means for determining the vertical position of thehearing aid microphones (e.g. a control unit) and means for compensatingfor a possible dislocation of the hearing aid microphones (e.g. aprocessing unit). Hereby the hearing aid device can provide an optimumsound experience for the hearing aid user due to the fact that thehearing aid device can compensate for a dislocation of the hearing aidmicrophones (dislocation of the hearing aid microphones occurs when thehearing aid microphones are not arranged in the same horizontal plane).

In the present context, a ‘vertical direction’ is taken to coincide witha direction of the gravitational force on a body at a given location.Similarly, a ‘horizontal plane’ is taken to be perpendicular to thevertical direction (and thus to a direction of the gravitational forceon a body) at the given location.

It may be an advantage that the means for determining the verticalposition of the hearing aid microphones comprises an accelerometer.

Dislocation of the hearing aid microphones can be determined by theaccelerometer, and the noise reduction (e.g. including a directional)system of the hearing aid device may hereby be modified in order tocompensate for the sub-optimal mounting. Therefore, when mounting ahearing aid device e.g. behind the ear, the positioning could beoptimised in order to improve the performance of different algorithms.

It may be beneficial that the hearing aid device comprises means fordetermining the direction of gravity.

Hereby knowledge about the direction of gravity can be used to determinethe optimal way to adjust the hearing aid device in order to e.g.achieve the vertical position of the hearing aid microphones. It wouldbe possible to determine how to adjust the processing in order tocompensate for microphone positions that are not optimal.

Since the noise reduction (e.g. including a directional) system of ahearing aid device to a certain extent relies on the assumption that themicrophones are located in the horizontal plane, optimal conditions forprocessing of the noise reduction (e.g. including a directional) systemcan be achieved when the microphones are located in the horizontal plane(see e.g. FIG. 4).

It may be beneficial that the hearing aid device comprises means fordetecting the direction of the hearing aid microphones of a pair ofhearing aid device. This means that for both the right and the lefthearing aid device the direction of the hearing aid microphones shouldbe determined. In the present context, the ‘direction of themicrophones’ is taken to mean the direction defined by a straight linejoining the two microphones (e.g. their geometrical centres).

It may be an advantage that the hearing aid device comprises an actuatorconfigured to change the orientation (inclination) of the hearing aidmicrophones. Hereby the actuator can bring the hearing aid microphonesinto an optimal position, and thus the most optimal sound experience canbe provided to the hearing aid user.

In an embodiment, the hearing aid device comprises a directional systemwith an adaptive directional algorithm for providing a combined signalbased on signals from the at least two hearing aid microphones.

In an embodiment, the hearing aid device comprises a feedback estimationunit comprising an adaptive feedback algorithm for estimating a feedbackpath from the output unit to the input unit.

It may be advantageous that the hearing aid device comprises means fordetecting movement of the head of the hearing aid user and means forchange the adaptation speed in one or more adaptive algorithms appliedby the hearing aid device. Hereby the hearing aid device can enhance thesound experience for the hearing aid user. In an embodiment, the controlunit is configured for changing the adaptation speed in one or moreadaptive algorithms applied to the audio signal by the hearing aiddevice.

In some situations it may be an advantage to increase speed of anadaptive algorithm in order to rapidly adapt the directivity pattern tonew surroundings. This may be the case when the hearing aid user ismoving the head. Hereby the user of the hearing aid device is providedwith a sound experience that is improved with respect to thedirectivity. In an embodiment, the change in direction is used to changethe directivity pattern according to the change in angle.

The advantage is that the directivity pattern can be calculated (oralternatively loaded) solely based on the existing directivity patternand the detected head movement, hereby applying a best guess for adirectivity pattern. Hereby the sound from the expected direction can becancelled out faster.

In an embodiment, the hearing aid device comprises a memory wherein areference position or an orientation of the hearing aid device isstored. In an embodiment, the hearing aid device is configured tocompare a current position of the hearing aid with the stored referenceposition and to determine a modified reference feedback path estimateused for determining the current setting of signal processing parametersused in the signal processing unit for modifying the audio signals. Inan embodiment, a reference feedback path estimate is stored in thememory. In an embodiment, the hearing aid device is configured tocompare a current feedback path estimate with the stored referencefeedback path estimate. This may e.g. be used to qualify the modifiedreference feedback path estimate used for determining the currentsetting of signal processing parameters.

In an embodiment, the hearing aid device is configured to determine saidmodified reference feedback path estimate used for determining thecurrent setting of signal processing parameters based on an algorithm ora lookup table with corresponding values of incremental position changesand feedback path and/or processing parameter values.

In an embodiment, the hearing aid device is configured to determine amodified reference feedback path estimate in connection with power up ofthe hearing device and/or after a mounting of the hearing aid device ator in an ear of the user.

In an embodiment, the hearing aid device is configured to continuouslymonitor the microphone positions. In an embodiment, the hearing aiddevice is configured to modify the reference feedback path estimateand/or the setting of signal processing parameters based on thecontinuously monitor the microphone positions.

In an embodiment, the hearing aid device wherein the setting of signalprocessing parameters comprises (e.g. frequency dependent) maximum gainvalues that may be applied to the audio signals to minimize the risk offeedback.

In an embodiment, the hearing aid device is configured to use thedifference in input level between the two hearing aid microphones todetect whether the user's own voice is present in the current acousticsignals received by the microphones and to provide an own voice controlsignal indicative thereof.

In an embodiment, the hearing aid device is configured to estimate areliability of the own voice control signal based on a comparison of thecurrent position of the hearing aid with the stored reference position.

It may be beneficial that the hearing aid device comprises a free falldetector and means for sending a signal to another device, e.g. anotherhearing aid device and/or an external (auxiliary) device. Hereby thehearing aid device is capable of preventing that the hearing aid islost. Moreover, by sending a signal to an external device, the hearingaid device may alert the hearing aid user and provide information thatcan be used to identify where and when the hearing aid device was lost.

It may be an advantage that the hearing aid device comprises a free falldetector and means for sending a signal to a mobile phone.

It may be beneficial that the hearing aid device comprises means forsending a signal when free fall is detected by means of the free falldetector. Hereby it is possible to log every time a free fall isdetected or to alert one or more individuals.

It may be an advantage that the hearing aid device comprises means fordetermining the location of the hearing aid device.

It may be an advantage that the hearing aid device comprises means forlogging the location of the hearing aid device.

It may be an advantage that the hearing aid device comprises means forwirelessly logging the location of the hearing aid device on an external(auxiliary) device e.g. a mobile phone.

In an embodiment, the hearing aid device is configured to use the sensormember (e.g. a free-fall detector) to estimate an impact shock on thehearing device from impingement on a surface after a free fall, and tolog such shock data. In a further embodiment, the configuration of theaccelerometer is changed, when free fall is detected. In order tomaximize the probability of recording the impact the sample rate of theaccelerometer should preferably be changed to its maximum sample rate.Also preferably, the sensitivity of the accelerometer is changed inorder to record as high accelerations as possible. As an example, whenfree fall is detected, change sample rate from 30 times per second to1000 times per second and change resolution from +/−2 g to +/−16 g.

In an embodiment, the hearing aid device is configured use the sensormember to detect if the hearing aid device is being moved and tocharacterize the movement (e.g. fast/slow, up/down, etc.), and whereinthe hearing aid device is configured to automatically turn off power orto be put into a ‘low-power’ or ‘sleep mode’ where the power consumptionis minimal, when the sensor member detects that the hearing aid deviceis in a no-movement mode.

In an embodiment, the hearing aid device is configured use the sensormember to detect if the hearing aid device is being moved and tocharacterize the movement (e.g. fast/slow, up/down, etc.), and whereinthe hearing aid device is configured to be automatically turned on in afull power-on mode or in a ‘standby mode’, when the sensor memberdetects that the hearing aid device is in a ‘movement mode’.

In an embodiment, the hearing aid device is configured to use the sensormember together with other sensors to detect whether or not the hearingaid device is located at or on the ears of a user, such detection beingused to influence a change of power mode. Thereby the decision to turnthe power fully or partially on or off can be influenced by otherparameters (provided by the ‘other sensors’) than movement and thus bemore taken on a more reliable basis.

Another common problem, in particular for elderly people, is related toaccentual falls, e.g. in unattended situations, e.g. at home. The reasonfor the fall can be several, however the problem is the same. If aperson is not able to move after the fall has occurred, the person maynot be able to call for help. One solution to the problem include a bodyworn device that the person can operate to call for help. However, insome cases the person who has fallen is not able to operate this deviceeither. Using a hearing aid device with a build-in movement sensor, e.g.an accelerometer, will enable an automatic evaluation whether the personwearing the hearing aid device has fallen. If this is combined with anauxiliary device, e.g. a SmartPhone (in that the hearing aid device isconfigured to transmit an indication that the person has fallen to theauxiliary device), an automatic alarm can be conveyed to another person.In case the auxiliary device comprises a cellphone, the phone may beconfigured to automatically call a pre-selected phone number to ahelping person. Utilizing the hearing aid devices, it will be possiblefor the helping person to communicate with the person in need of help.

Objects of the present disclosure can be achieved by a hearing aidsystem that comprises two hearing aid devices according to the claims.

In an embodiment, each of the the two hearing aid devices comprisesantenna and transceiver circuitry for establishing a communication linkto the other hearing device, and thereby allowing the exchange ofinformation between them.

In an embodiment, at least one of the two hearing aid devices comprisesmeans for determining the angle between the hearing aid devices on thebasis of measurements made by means of the sensor member(s) in the twohearing devices.

Hereby, an optimum sound experience can be provided to the hearing aiduser by means of both hearing aid devices.

In an embodiment, the hearing aid system configured to provide that anestimated reliability of the own voice control signal is based on acomparison of the current position of the hearing aid device with thestored reference position of the hearing aid device in each of the twohearing aid devices (i.e. the results of the respective comparisons areexchanged between the two hearing aid devices, compared and used todecide on whether the user's voice is currently present or not).

In an embodiment, the hearing aid system further comprises an auxiliarydevice. In an embodiment, the hearing aid system is configured to allowthe hearing aid devices and the auxiliary device to communicate witheach other (e.g. via wireless links, e.g. based on radiated fieldsand/or on near-field communication, e.g. inductive coupling). In anembodiment, the auxiliary device also contains a movement sensor (e.g.an accelerometer), so that (based on the acceleration patterns in thehearing devices and the acceleration pattern in the auxiliary device) itcan be determined if the auxiliary device is carried on the body (inwhich case both devices have the same movement pattern), and controllingthe functionality according to that. An auxiliary device lying at atable could e.g., by use of this sensor input in combination with otherinputs, automatically be used as an extra microphone.

It may be beneficial that the angle may be determined on the basis ofthe direction of the acceleration in each hearing aid device.

It may be an advantage that the hearing aid system comprises means fordetermining the location of the hearing aid device(s).

Hereby the hearing aid system is capable of logging information orsending information about the location of the hearing aid system. Thismay be an advantage if one of the hearing aid devices is lost ordamaged.

It may be an advantage that the hearing aid system comprises means tolog the position where the free fall is detected.

Hereby the hearing aid system can be used to track a lost hearing aiddevice in an easy way, since the position (and optionally the time) atwhich a free fall is available.

It may be an advantage that the hearing aid system comprises a GPSdevice that receives Global Positioning System (GPS) signals todetermine the location of the hearing aid devices.

It may be an advantage that the hearing aid system comprises a mobilephone that comprises a GPS device capable of receiving GlobalPositioning System (GPS) signals to determine the location of thehearing aid device and means to log the position at which a free fall isdetected. This has the advantage over e.g. a detection based on lostwireless connection, because the position is logged at the exact placewhere the hearing instrument is dropped, and an audible or visualwarning may also be provided earlier. Alternatively, the location couldbe based on WiFi hotspots or whatever localization tool is available forthe auxiliary device.

It may be beneficial that the hearing aid system comprises means fordetermining the angle between the hearing aid devices on the basis ofmeasurements made by means of the sensor member.

It may be an advantage that the hearing aid devices comprise means forindividually mapping overlapping parts of the sound scene surroundingthe hearing aid user and that each of the hearing aid devices comprisesmeans for exchanging information about directions and soundcharacteristics to the other hearing aid device.

This will allow the other hearing aid device to recognise the soundsources when they enter their scope of acoustic view when the hearingaid user is turning the head.

The hearing aid device may comprise means for detecting the hearing aiduser's heartbeat. The hearing aid device moreover may comprise means forproviding a signal processing based on the heartbeat informationprovided by the hearing aid device.

In situations in which the heart rate is increased a specific signalprocessing may be advantageous in order to ensure a good environmentalawareness.

If the hearing aid user is performing outdoor sports and or if thehearing aid user faces dangerous situations, where the hearing aid usershould not miss surrounding sounds, it may be of great importance to beable to provide an optimum sound experience.

On the other hand, when the end user is relaxed, the signal processingcan be adapted to give a smooth sound that supports this relaxed state.

The hearing aid device may comprise means for detecting the heart beatby using a dedicated microphone that is placed next to the sound outletin the ear canal. This microphone may be connected to the hearing aiddevice in which the signal processing is carried out.

It may be an advantage that the microphone signal (from the dedicatedmicrophone) is lowpass-filtered, because only very low frequencies (e.g.around or below 50 Hz) are relevant. Hereby, the influence ofenvironmental sound or the sound presented by the hearing instrument atthe outlet will also be minimized.

In fact, the environmental sound (direct sound) will be picked up by the“regular” hearing aid microphones. Therefore, it is possible to estimatethe properties of the environmental sound picked up by the extra(dedicated) microphone in the ear canal and to suppress it.

Likewise, the regular microphone signal (or a signal derived therefrom,e.g. filtered or combined with another signal) that is played back bythe hearing aid device is also known and can possibly be subtracted fromthe signal picked up by the extra microphone in the ear canal.

When the signal picked up by the extra microphone in the ear canal hasbeen cleaned up from environmental sound and amplified sound from thehearing instrument, it can be used to detect fairly regularlow-frequency level modulations in the order of up to 3 Hz.

The robustness of this estimation can be increased in bilateralfittings, because the heart beat is assumed to be absolutely synchronousin the left and right ear canal.

Closed fittings are advantageous, because they block out environmentalsound and the closure of the ear canal may help to increase lowfrequency levels present in the ear canal. When the heart rate changes,the blood flow in the ear canal may also change. Hereby it is likelythat the feedback path will also change, and the functionality of thehearing device can be controlled in dependence of such changes.

DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detaileddescription given herein below. The accompanying drawings are given byway of illustration only, and thus, they are not limitative of thepresent invention. In the accompanying drawings:

FIG. 1 a) shows a view of a hearing aid user 4 during a physicaltraining session;

FIG. 1 b) shows a close-up view of the hearing aid device 2 that thehearing aid user shown in FIG. 1 a) is wearing;

FIG. 1 c) is a histogram showing the physical activity over time of thehearing aid user shown in FIG. 1 a) determined by using a hearing aiddevice according to the disclosure;

FIG. 1 d) shows a hearing aid user watching television;

FIG. 1 e) is a histogram showing the physical activity of the hearingaid user shown in FIG. 1 d);

FIG. 2 a) schematically shows a view of the parameters used to defineindividual hearing aid device settings;

FIG. 2 b) shows a hearing aid user during a physical training session;

FIG. 2 c) shows the hearing aid user shown in FIG. 2 b) relaxing infront of a television;

FIG. 3 a) shows a top view of a hearing aid user standing next to asound source;

FIG. 3 b) shows a top view of the hearing aid user shown in FIG. 3 a)turning the head;

FIG. 4 a) shows a hearing aid device provided with an accelerometer andtwo microphones arranged in the same horizontal plane;

FIG. 4 b) shows a hearing aid device provided with an accelerometer andtwo microphones that not are arranged in the same horizontal plane;

FIG. 5 a) shows a view of a hearing aid user wearing a BTE hearing aiddevice having two microphones that are used to detect the voice of thehearing aid user.

FIG. 5 b) shows another view of the hearing aid user wearing the BTEhearing aid device shown in FIG. 5 a);

FIG. 6 a) shows a side view of a hearing aid device arranged behind theear of a hearing aid user;

FIG. 6 b) shows another side view of a hearing aid device arrangedbehind the ear of a hearing aid user;

FIG. 6 c) shows a further side view of a hearing aid device arrangedbehind the ear of a hearing aid user;

FIG. 7a ) shows a hearing aid device provided with an actuatorconfigured to change the orientation of the hearing aid microphones;

FIG. 7 b) shows another view of a hearing aid device provided with anactuator configured to change the orientation of the hearing aidmicrophones;

FIG. 8 shows two coils arranged in a hearing system comprising twohearing aid devices, the two coils being arranged in each theirrespective hearing aid device;

FIG. 9 a) shows a schematic top view of a hearing aid user standing infront of two individuals that are talking to him;

FIG. 9 b) shows a schematic top view of the hearing aid user shown inFIG. 9 a) in a situation where he has turned his head clockwise;

FIG. 10 a) shows a situation where a hearing aid device is dropped bymistake and

FIG. 10 b) shows another situation where a hearing aid device is droppedby mistake.

FIG. 11 a) illustrates a definition of the rotational movementparameters pitch, yaw and roll relative to the x, y and z axis of anorthogonal coordinate system (left) and relative to a head of a user(right).

FIG. 11 b) illustrates the centripetal force F_(s)=mrω² in an angularmovement.

FIG. 12 a) illustrates the estimation of angular velocity of a head byan accelerometer located in a hearing aid device.

FIG. 12 b) illustrates a first method of estimation of angular velocityof a head by an accelerometer located in each hearing aid device of abinaural hearing aid system.

FIG. 12 c) illustrates a second method estimation of angular velocity ofa head by an accelerometer located in each hearing aid device of abinaural hearing aid system.

FIG. 13 illustrates a non-ideal location of the two hearing aid devicesof a binaural hearing aid system, where the center of rotation of thehead is NOT located on a straight line connecting the two hearing aiddevices.

FIG. 14 a) illustrates a first embodiment of a hearing aid system (A)for automatic on/off detection.

FIG. 14 b) illustrates a second embodiment of a hearing aid system (B)for automatic on/off detection.

DETAILED DESCRIPTION OF THE INVENTION

Referring now in detail to the drawings for the purpose of illustratingpreferred embodiments of the present disclosure, a close-up view ofhearing aid device 2 according to the disclosure is illustrated in FIG.1 b).

Usage Pattern of a Hearing Aid Device:

The exemplary hearing aid device 2 is a BTE hearing aid device 2comprising a BTE part adapted for being located at or behind and ear andan ear piece, e.g. an ear mould 10, inserted into the ear 6 (e.g. an earcanal) of a hearing aid user 4 as illustrated in FIG. 1 a). The hearingaid user 4 is performing physical exercise, e.g. running.

In FIG. 1 b) it can be seen that a tube 12 that acoustically connects aloudspeaker of the the casing of the BTE part of the hearing aid device2 and the ear mould 10. It might alternatively or additionally comprisea cable for electrically connecting electric components in the BTE partof the hearing aid device 2 (e.g. a processor) to an electric component,e.g. a loudspeaker, located in the ear mould 10 (or otherwise positionedin the ear canal of the user, e.g. via an open mould, or a resilientdome).

The hearing aid device 2 comprises a sensor member 8 that is configuredto detect motion of the hearing aid device 2 and thus the level ofphysical activity of the hearing aid user 4. The sensor member 8comprises an accelerometer or a gyroscope or both. By means of theaccelerometer and/or gyroscope the hearing aid device 2 is capable ofdetermining the level of physical activity of the hearing aid user 4.The duration as well as the intensity of activities of the hearing aiduser 4 may be determined by means of the sensor member 8 by loggingmeasured data over time. Large linear and angular accelerations andvelocities indicate a high level of activity, while low or moderatelinear and angular accelerations and velocities indicate a moderate orlow level of activity (threshold values between large and medium (ande.g. low) for each parameter being e.g. defined in advance of operationof the hearing aid device).

FIG. 1 c) illustrates a histogram 18 showing the level of physicalactivity of the hearing aid user 4 (as illustrated in FIG. 1a ))determined by using the hearing aid device 2 shown in FIG. 1 b). Thelevel of physical activity 16 is depicted as function of time 14.

FIG. 1 d) illustrates a view of a less active hearing aid user 4′watching television. The hearing aid user 4′ is wearing a hearing aiddevice 2 according to the disclosure.

FIG. 1 e) illustrates a histogram 18 showing the physical activity 16 ofthe hearing aid user 4′ shown in FIG. 1 d). The physical activity of thehearing aid user 4′ is determined by using the hearing aid device 2. Thelevel of physical activity 16 is depicted as function of time 14. WhenFIG. 1 c) is compared to FIG. 1 e) (e.g. by comparing averaged values oflevel over a specific time or some other statistical ‘distance measure’)it can be seen that the level of physical activity 16 generally is lowerfor hearing aid user 4′ compared to hearing aid user 4.

The hearing aid device 2 according to the disclosure may log and storedata representing the level of physical activity of the hearing aidusers 4, 4′.

The hearing aid device 2 according to the disclosure makes it possibleto set the preferred speed of the compression system and the preferredaggressiveness of the noise reduction system individually of hearing aiduser 4, 4′ based on actual measurements of the level of physicalactivity 16. Moreover, prior knowledge about the user's individualbehaviour (e.g. on the basis of logged data) may be used to optimise thehearing aid device settings for each user on an individual basis.

The hearing aid user 4 who is physically active may prefer a hearing aiddevice 2 with more aggressive settings (such as faster time constants inthe compression system or a more aggressive setting for the noisereduction) compared to the other hearing aid user 4′ who is less activeduring the day. Alternatively, or additionally, the hearing aid settingsfor a particular user may be (dynamically) varied over time independence of the user's current level of activity.

FIG. 2 a) illustrates a schematical view of a number of parameters 22,24, 26, 28, 30 used to define individual hearing aid device settings 20.These parameters may include the following categories: level of physicalactivity 22, age 24, cognitive skills 26 (e.g. cognitive (spare)capacity, such as working memory capacity), own voice program 28 and anextra “open” category 30 that may be used for any individually definedcategory.

Accordingly, by using hearing aid device settings 20 as illustrated inFIG. 2 a), the hearing aid settings depend on several parameters 22, 24,26, 28, 30 including age 22, cognitive skills 24 or how much the hearingimpaired person is talking. Thereby, it is possible to set the hearingaid device settings individually, e.g. determined or influenced by oneor more of these parameters in combination with the estimate of theuser's current (or average) physical activity.

An accelerometer and/or a gyroscope built-in to the hearing aid device 2can be used to estimate the physical activity level of the individualhearing aid user 4, 4′ during the day. Additionally, the activity levelmay be estimated by measuring the amount of loudness during the day(e.g. an accumulated sound dose) as well as e.g. the exposure to windnoise, e.g. by logging such parameters over time.

It may (for some tasks) be more advantageous that an accelerometerand/or a gyroscope is built into the hearing aid device 2 compared to ahand held device (such as a mobile phone), because the hearing aiddevice is attached to the body of the hearing aid user during the wholeday. Furthermore, contrary to e.g. a mobile phone, the hearing aids arealways positioned in a similar way. Hereby, the accelerometer and/or agyroscope may provide a more accurate estimate of a hearing aid user'slevel of physical activity. An accelerometer and/or a gyroscope in ahand-held device may, however; be used in connection with the hearingaid device according to the disclosure in order to estimate the level ofphysical activity.

FIG. 2 b) illustrates a running hearing aid user 4′ during a trainingsession. The hearing aid user 4′ is wearing a hearing aid device 2according to the disclosure. The hearing aid device 2 comprises a sensormember (comprising an accelerometer and/or a gyroscope) that detectsthat the hearing aid user 4′ has a high level of physical activity.Therefore, a predefined preferred set of settings P₁ is applied.

FIG. 2 c) illustrates a situation where the hearing aid user 4′ hasreturned from the training session and is relaxing in front of atelevision. The hearing aid user 4′ is wearing the same hearing aiddevice 2 as in FIG. 2 b). Accordingly, the sensor member detects thatthe hearing aid user 4′ has a low level of physical activity. Therefore,the predefined preferred set of settings is automatically changed fromP₁ to P₂.

The hearing aid device 2 may comprise means for changing the settingsP₁, P₂ (with a predefined speed) over time based on the different input,including the level of physical activity detected by means of thehearing aid device 2. It is possible to have a hearing aid device 2, inwhich the hearing aid device settings change automatically while theuser 4′ is wearing the hearing aid device 2 based on measurements fromthe sensor member. This may be done in combination with simultaneouslyapplication of other detectors. In this way it would be possible tochange settings when environment parameters change and/or when the levelof physical activity of the hearing aid user 4′ wearing the hearing aiddevice 2 changes.

Thus, the settings of the hearing aid device 2 may be optimised for user4′ of the hearing aid device 2. It is possible that the hearing aiddevice settings slowly adapt over time on the basis of measurements fromthe accelerometer and/or a gyroscope built-in to the hearing aid device2. Hereby, these measurements optionally in combination with otherdetectors may change the hearing aid device settings when environmentchanges occur or when the activity level of the user 4′ changes.

Measurements from the accelerometer and/or a gyroscope built-in to thehearing aid device 2 may be used as part of a fitting tool, where theactivity level might be combined with measurements of the environmentprovided by the hearing aid device 2 or by another device (e.g. a mobilephone) in a situation where this information define preferences of theuser 4′. This may be done while switching between different hearing aiddevice programs corresponding to different levels of activity as shownin FIG. 2 b) and FIG. 2 c) or when changing the settings in a hearingaid device 2 with a remote control (e.g. implemented as an APP in amobile phone, e.g. a SmartPhone).

When repeated measurements have been carried out in similar environmentsfor a period of time (e.g. a few weeks) the hearing aid device settingsmay be able to automatically adjust to the user's 4′ preferences.Different user's preferences may be logged by the hearing aid device 2and collected in a network. Hereby, individual preferences may befurther used in the development, where the preferred settings may belogged and used to find optimal settings for other similar users insimilar environments.

The measurements may be analysed by a professional (hearing aiddispenser) and/or be used by the fitting software, and the hearing aiddevice settings could be individualised based on this.

The measured activity may also be further labelled, e.g. situationswhere the user 4′ is laying down, running or driving in a car mayautomatically be detected by the accelerometer and/or a gyroscopebuilt-in to the hearing aid device 2 and be used as specific inputs forthe hearing aid settings adjustment.

Spatial Improvement of Sounds without Built-in Localization Cues:

FIG. 3 a) illustrates a schematical top view of a hearing aid user 4standing next to a loudspeaker 32 sending out sound 34 towards the leftear of the user. A hearing aid device 2 is arranged at or in both ears2.

FIG. 3 b) illustrates a schematical top view of the hearing aid user 4shown in FIG. 3 a) turning his head. The head is moved from a firstposition I to a second position II.

Since an accelerometer and/or a gyroscope is built-in to the hearing aiddevices 2 the accelerometers and/or gyroscopes will detect that thehearing aid devices 2 are moved.

Artificial sounds 34 in the hearing aid device(s) 2 such as e.g.internal beeps or streamed stereo sounds may be convolved byhead-related impulse responses (HRIR) in order to make the sounds appearas coming from a certain direction (such as appearing to the left of thehearing aid user 4). When the hearing aid user 4 turns his head, theartificial sound 34 will still appear as it is impinging from the left,hereby partly ruining the spatial experience.

The accelerometer and/or a gyroscope built-in to the hearing aiddevice(s) 2 detect the degree of head movement. This information may beused to adaptively change the head-related impulse response in order tocreate the illusion that the artificial sound 34 appears to be at thesame location IV in the room.

The fastest change of the acoustic surroundings with respect to thehearing instruments is usually when the listener wearing the hearinginstrument is moving or turning its head. A hearing aid device 2 with abuilt-in accelerometer and/or gyroscope is able to estimate suchmovement of the head of the hearing aid user 4. If such a movement isdetected, the spatial perception of an artificial sound 34 or any soundwhich is not directly picked up by the hearing aid microphones may beimproved when compensating for the head movement.

FIG. 3 a) illustrates how a built-in accelerometer and/or gyroscope maybe used to improve the spatial perception of an artificial sound 34. Anartificial sound 34 (e.g. beep, streamed sound, TV sound signal,telecoil sound or an FM signal comprising a sound signal, e.g. from amicrophone) may be convolved by a head-related impulse response in orderto create the illusion that the sound 34 is impinging from a certaindirection (such as e.g. to the left side of the head indicated withposition IV). If, however the hearing aid user 4 is turning his head,the sound will still seem to impinge from the left side, hereby partlyruining the externalization illusion.

Continuous information about the degree of head movement obtained by anaccelerometer and/or gyroscope may be used to adapt the head-relatedimpulse response towards another direction. This requires that thehearing aid device(s) 2 have access to a database of head-relatedimpulse responses (or alternatively in the frequency domain head-relatedtransfer functions, HRTF) in samples with a reasonable degree ofresolution (e.g. in spatial coordinates, e.g. in azimuthal (φ), andpossibly polar (θ), angle(s)) allowing a seamless change in perceiveddirection.

Optimized Mounting of Hearing Aid Devices:

FIG. 4 a) illustrates a schematical view of a hearing aid device 2provided with an accelerometer and two microphones 38, 38′ that arearranged in the same horizontal plane H indicated by a dotted line.

The hearing aid device 2 is a BTE hearing aid device 2 arranged at orbehind the ear 6. The hearing aid device is connected to an earpiecearranged in the ear canal via a tube 12.

If the hearing aid user is running or moving the acceleration acc willbe detected by the accelerometer. The noise reduction (e.g. including adirectional) system of a hearing aid device often relies on theassumption that the microphones 38, 38′ are actually located in thehorizontal plane H as shown in FIG. 4 a). Accordingly, optimalconditions for processing of the noise reduction (e.g. including adirectional) system can be achieved when the microphones 38, 38′ arelocated in the horizontal plane H. This is, however, not alwaysachieved. The amount of dislocation can be determined by theaccelerometer, and the noise reduction (e.g. including a directional)system may hereby be modified in order to compensate for the sub-optimalmounting.

Therefore, when mounting a hearing aid device 2 behind the ear 6, thepositioning could be optimised in order to improve the performance ofdifferent algorithms.

The accelerometer is able to estimate the direction of the gravity g.Knowledge about the direction of gravity g (relative to a fixeddirection of the hearing aid device 2, e.g. the direction of themicrophones, H_(s) in FIG. 4 b), assuming that g is perpendicular to themicrophone direction, when the hearing aid device is correctly mounted)can be used to determine how the hearing aid device 2 should be adjustedin order to e.g. achieve a horizontal position of the hearing aidmicrophones 38, 38′ (so that H_(s)=H, φ=0). It would be possible todetermine how to adjust the processing in order to compensate formicrophone positions that are not optimal.

The positions of the microphones can be compensated based on an instantmeasurement of position, where the person is looking straight forward,but the position could also be determined as an average position basedon how the person actually is carrying the hearing instruments. If e.g.the person most of the time is bending the head forward due to backproblems, it is better adjusting the hearing instrument angle accordingto that.

Typically the noise reduction (e.g. including a directional) systemassumes that the listener is listening to the sound impinging from thefront (look direction), and the noise reduction (e.g. including adirectional) system is thus optimized in order to provide a flatfrequency response from the front direction. If the hearing aidmicrophones 38, 38′ are not located along the horizontal axis H, thenoise reduction (e.g. including a directional) system may be modified inorder to provide a flat frequency response of the “new” look direction.

FIG. 4 b) illustrates a hearing aid device 2 provided with anaccelerometer and arranged in a position in which the microphones 38,38′ are not arranged in the same horizontal plane H. In this case theaccelerometer will determine the direction of gravity g (e.g. relativeto H) and the hearing aid device be configured to compensate for themisalignment (with respect to horizontal) of the microphones 38, 38′ bymodifying the noise reduction (e.g. including a directional) system.This addresses the case, where it is not possible to obtain an optimal(horizontal) microphone configuration. The directional microphonecoefficients can be changed to an optimal configuration, which takesinto account that the microphone configuration is not optimal.

In an embodiment, the noise reduction system comprises amulti-microphone beamformer (e.g. an MVDR beamformer) and a singlechannel post filter (as e.g. described in [Kjems & Jensen; 2012] (ISSN2076-1465: Ulrik Kjems and Jesper Jensen, “Maximum likelihood basednoise covariance matrix estimation for multi-microphone speechenhancement”, 20th European Signal Processing Conference (EUSIPCO 2012),pp. 295-299, 2012)).

FIG. 5 a) illustrates a view of a hearing aid user 4 wearing a BTEhearing aid device 2 having two microphones that are used to detect thevoice of the hearing aid user 4.

Often the detection of the voice of the hearing aid user 4 relies on thefact that one microphone is arranged in a larger distance from the mouth36 than the other microphone. This is the case in FIG. 5 a) since thedistance d₂ between the mouth 36 and the furthermost microphone of thehearing aid device 2 is larger than the distance d₁ between the mouth 36and the nearest microphone of the hearing aid device 2. Because themouth 36 is close to the hearing aid microphones, an intensitydifference between the microphones can be detected (acousticnear-field). This difference may be used to detect the voice of thehearing aid user 4.

In FIG. 5 b) the hearing aid device 2 is tilted and thus the microphonesare no longer arranged in the same horizontal plane. The mouth directionmay be close to perpendicular to the line crossing the hearing aidmicrophones. This means that the distance d′₂ between the mouth 36 andthe furthermost microphone of the hearing aid device 2 basicallycorresponds to the distance d′₁ between the mouth 36 and the nearestmicrophone of the hearing aid device 2. Accordingly, the microphoneswill have basically the same distance (d′₁˜d′₂) to the mouth 36, and thenear-field cue for own voice detection is not reliable.

Since the hearing aid device 2 comprises an accelerometer, the directionof the hearing aid microphones can be estimated by means of theaccelerometer. Accordingly, based on the detected direction of thehearing aid microphones it can be determined whether or not the ownvoice cue is reliable.

In one embodiment of the disclosure the reliability of the own voicedetection may be based on the detected direction of the hearing aidmicrophones of both hearing aid device 2 (left and right) of a binauralhearing aid system. It may be predefined that only in the case thatdetection for both ears is accessed and only if the angle of the hearingaid microphones with respect to the mouth 36 results in a reliable cue,the detection should be used (assuming that such information can beexchanged between the two hearing aid devices, e.g. via a wireless link,e.g. an interaural, e.g. inductive wireless link). This could e.g. bemeasured during fitting (or another calibration routine) because theangle should be measured when the person is looking straight ahead. FIG.6 a) illustrates a side view of a hearing aid device 2 arranged behindthe ear 6 of a hearing aid user. The hearing aid device 2 comprises afirst microphone 38 and a second microphone 38′. The microphones 38, 38′are arranged along a line H_(s) that is not parallel to horizontal planeor direction H. The angle φ of the hearing aid device 2 is defined asthe angle between the line H_(s) and horizontal H.

The BTE part and the ear piece of the hearing aid device are connectedand arranged in the ear canal via a (typically resilient) tube 12. Thelength of the tube 12 influences the way the BTE part fits behind theear, and thus also the positioning of the microphones 38, 38′. Duringfitting of the hearing aid device 2, the optimal length of the tube 12of the hearing aid device 2 can be determined by measuring the angle φof the hearing aid device 2 based on measurements provided by means ofthe accelerometer. This is illustrated in FIG. 6.

In FIG. 6 a), the initial guess of the length of tube 12 is too long andthus the hearing aid device 2 points upwards and the first microphone 38and the second microphone 38′ are not arranged in the same horizontalplane (when the user is standing in an upright position, e.g. on theground (assuming a vertical direction)). The microphones 38, 38′ arearranged along a line H_(s) that is not parallel to horizontal H.Therefore, the angle φ is non-zero (positive).

The accelerometer of the hearing aid device 2 provides measurements ofthe acceleration acc having components 42, 44. The accelerometer of thehearing aid device 2 also detects the direction of gravity g. Based onthese measurements the angle φ of the hearing aid device 2 (angle ofH_(s) with H) can be established and it can be determined how much thecurrent tube 12 should be adjusted in order to place the hearing aiddevice 2 in an optimal position.

FIG. 6 b) illustrates another side view of a hearing aid device 2arranged behind the ear 6 of a hearing aid user. The initial tube 12guess is too short and thus the hearing aid device 2 points downwards(the angle φ between directions H_(s) and H has an opposite sign than inthe example of FIG. 6 a)). The first microphone 38 and the secondmicrophone 38′ are not arranged in the same horizontal plane. Themicrophones 38, 38′ are arranged along a line H_(s) that is not parallelto horizontal H. Accordingly, the angle φ is non-zero (negative). Basedthereon, it can be determined how much the current tube 12 should beadjusted in order to place the hearing aid device 2 in an optimalposition.

FIG. 6 c) illustrates another side view of a hearing aid device 2arranged behind the ear 6 of a hearing aid user. The length of the tube12 is optimal and thus both the first microphone 38 and the secondmicrophone 38′ are arranged in the horizontal plane H. The microphones38, 38′ are arranged along a line H_(s) that is parallel to horizontalH. Accordingly, the angle φ between H_(s) and H is zero.

The accelerometer of the hearing aid device 2 detects the direction ofgravity g and the angle φ of the hearing aid device 2. It can beverified that the current tube 12 has an optimum length and that noadjustment either of the length of the tube 12 or the position of thehearing aid device 2 is required.

Based on the measured angle φ of the hearing aid device 2 may similarlybe applied to determine the optimal cable length of a (resilient,semi-rigid) electric cable connecting a BTE part and a loudspeakerlocated in the ear canal and electrically driven from (a processor of)the BTE part of the hearing aid device (e.g. a hearing aid device of the‘Receiver In The Ear’ (RITE) type).

FIG. 7 a) illustrates a hearing aid device 2 provided with a smallactuator 46 configured to change the orientation (inclination) of thehearing aid microphones 38, 38′. The actuator 46 is capable of bringingthe hearing aid microphones 38, 38′ into an optimal position.

The hearing aid device 2 has a built-in accelerometer 8 adapted todetermine the direction of gravity g and the orientation of the hearingaid device 2 relative to the direction of gravity g.

In FIG. 7 a) the hearing aid microphones 38, 38′ are arranged along aline H_(s) that is parallel to horizontal H. Thus, there is no need toadjust the position of the microphones 38, 38′ relative to each other.

In FIG. 7 b) though, the position of the hearing aid microphones 38, 38′is changed from a first position I in which the hearing aid microphones38, 38′ are arranged along a line H_(s) that is not parallel tohorizontal H (ANGLE(H,H_(s))=φ) into a second position II in which thehearing aid microphones 38, 38′ are arranged in the horizontal plane(H_(s)=H). The actuator 46 is indicated with a dotted line in the firstposition I. The actuator 46 is indicated with a solid line in the secondposition II.

The actuator 46 brings the hearing aid microphones 38, 38′ from thefirst position I into the second position II and hereby bringing thehearing aid microphones 38, 38′ into the desired position. The angulardisplacement of the line (H_(s)) crossing the hearing aid microphones38, 38′ corresponds to the indicated angle φ.

In the first position I, the hearing aid microphones 38, 38′ arearranged along the non-horizontal line H_(s) and the expected directionof gravity 42 does not correspond to the direction of gravity g. Gravityg indicated as a vector g corresponds to the sum of the components 42and 44.

When the accelerometer 8 detects the direction of gravity g, thesecomponents 42, 44 can be calculated and the required adjustment of thehearing aid microphones 38, 38′ can be carried out by means of theactuator 46, as illustrated in FIG. 7 b).

FIG. 7 a) and FIG. 7 b) illustrate a hearing aid device 2 equipped witha small actuator 46 able to adjust the hearing aid microphones 38, 38′into e.g. a position where the hearing aid microphones 38, 38′ arepositioned in the same horizontal plane H, hereby optimising the effectof the directionality and/or the own voice detection of the hearing aiddevice 2.

FIG. 8 illustrates two coils 48, 48′ arranged in a hearing systemcomprising two (first and second) hearing aid devices.

The coils 48, 48′ may be used to provide communication between thehearing aid devices via magnetic inductance. The distance between thehearing aids may also be determined on the basis of the received signalpower (or signal strength; signal strength falls off with d³ (signalpower with d⁶) where d is the distance between the exiting an the exitedcoils). The received signal strength by a second inductive coil from afirst coil depends on the mutual orientations of the two coils. Anoptimum mutual induction between the two coils can be achieved, if thelongitudinal directions of the coils are parallel (as is nearly the casein FIG. 8). If not, the mutual induction is decreased from the optimum.Hence, the distance may be determined more accurately if the angle αbetween the hearing aid devices (e.g. the coil antennas 48, 48′) isdetermined (based on the transmitted and received signal strength andthe angle α). The angle α may be determined on the basis of thedirection of the acceleration acc in each hearing aid device.

FIG. 8 illustrates how the angle α between two accelerometers—one ineach hearing aid device can be used to improve the calculation of thedistance between the two ears based on the strength of the interauralmagnetic inductance.

Thus, it is beneficial that if a hearing system comprising two hearingaid devices is equipped with accelerometers capable of determining theacceleration acc in each hearing aid device and to compare the directionof the detected the acceleration vectors acc (acc1, acc2) to thedirection of gravity g.

Control of an Adaptive Algorithm:

FIG. 9 a) illustrates a schematical top view of a hearing aid user 4(wearing hearing aid devices 2, 2′ at his left and right ear,respectively) standing in front of two individuals 5, 5′ that aretalking to him. Two individuals 5″, 5′″ are talking to each other in thehatched area behind the hearing aid user 4.

FIG. 9 b) illustrates a schematical top view of the hearing aid user 4from FIG. 9 a) in a similar situation but where he is turning his headclockwise (cf. curved arrow).

Each of the hearing aid devices 2, 2′ comprises an accelerometer and/ora gyroscope that is configured to detect the acceleration of the hearingaids 2, 2′ and thus the acceleration of the hearing aid user 4.

FIG. 9 b) shows a situation in which the hearing aid user 4 turns hishead. Thus, the acoustic surroundings change. Hereby spatial algorithmsin the hearing aid devices 2, 2′ (e.g. a noise reduction (e.g. includinga directional) algorithm for defining a resulting microphonecharacteristic, a noise reduction algorithm, or a feedback estimationalgorithm) need to re-adapt to the new acoustic setup. Theaccelerometers and/or gyroscopes in the hearing aid devices are able todetect head movements. Based on the detected acceleration it is possibleto adjust the adaptation speed for the adaptive algorithm applied withinthe hearing aid devices 2, 2′.

The detected acceleration/movement can be used to provide the spatialalgorithms with information concerning the change of the acousticsurrounding. Accordingly, the spatial algorithms can increase theadaptation speed for a while in order to provide a fast adaptation tothe new acoustic environment.

By means of accelerometers and/or gyroscopes provided in the hearingaids it is possible to detect when it is an advantage to change theadaptation speed in the adaptive algorithm e.g. in order to increase itsspeed in order to rapidly adapt the directivity pattern to newsurroundings.

The directions to be attenuated by the hearing aid are indicated as thenon-hatched the area.

Feedback Path Variation Due to Placement of Hearing Aid Device(s):

During a fitting process, a standard feedback path is typically measuredwhen the hearing aid device(s) is/are correctly mounted at or in theear(s) of the user. The feedback path estimate is used as a referencevalue to set feedback-limits in the hearing aid device(s). However,variations in how the hearing aid device(s) is/are subsequently placedon the ear of the user, affects the feedback path and, thus, feedbackperformance of the hearing aid device(s).

Knowing the microphone positions relative to the positions during thereference measurement will make it possible to make a correction to the(reference) feedback path estimate (to modify derived gain parameters),and thereby maintain good feedback performance.

The problem is relevant for air conduction as well as bone conductionhearing aid devices. The latter (when bone anchored, e.g. using apartially implanted screw) meet a special challenges, since they canrotate around the screw where they are mounted.

A hearing aid device equipped with a sensor member for detecting themovement and/or acceleration and/or orientation and/or position of thehearing aid device when mounted on or at the user's ear will allow foraccessing nay possible variations in the position of the hearing aidmicrophones relative to the (reference) position they had when thereference feedback path was measured (e.g. the intended mountingposition). Preferably, a reference position of or an orientation of aparticular hearing aid device (e.g. a direction of a line through thegeometrical centers of the at least two hearing aid microphones relativeto a direction of the force of gravity) is stored in a memory of thehearing aid device.

When a current position of the hearing aid (in particular the hearingaid microphones) is determined (e.g. in connection with power up of thehearing device, after a mounting of the hearing aid device(s)) acomparison of the stored reference position with the measured currentposition, allows a modification of the reference feedback path estimateused for determining the current gain settings, e.g. based on analgorithm or a lookup table with corresponding values of incrementalposition changes and feedback path and/or maximum gain.

In an embodiment, the hearing aid is configured to continuously monitorthe microphone positions and when needed to modify current feedbacklimits (or maximum gain).

Sound Source Mapping:

Both hearing aid devices 2, 2′ detect sound from the surroundings of thehearing aid user. When the hearing aid user 4 moves the head, it wouldbe beneficial to have a 360 degree sound scene mapping corresponding tothe movement of the head of the hearing aid user 4.

Hearing instruments traditionally use directionality to emphasize soundsfrom the front and attenuate sounds from the sides and the back. Somesystems, however, allow switching of focus to the sides or the back. Inreality, the hearing aid user 4 will constantly turn the head to attendto objects of interest and the acoustic focus direction will turn withthe head movements causing the focus sound source (e.g. the person 5speaking) to get out of focus. The result is reduction or fluctuatingaudibility and intelligibility.

It may be an advantage to have a hearing aid system comprising twohearing aid devices 2, 2′ that are configured to work together(supported by wireless interaural communication between them). Hereby itis possible to analyse the sound environment and to detect thedirections and properties of individual sound sources 5, 5′, 5″, 5″,dynamically. When the hearing aid user 4 turns his head, the hearing aidsystem detects the movement and adjusts the focus direction(s)accordingly, to maintain audibility and intelligibility of the focussource 5 (or sources 5, 5′, 5″, 5′″, in case all four sources 5, 5′, 5″,5′″ are defined as focus sources).

The focus sources illustrated in FIG. 9 are individuals 5, 5′, 5″, 5′″.However, the focus sources may be a sound source (e.g. a person 5speaking) primarily in front of the hearing aid user 5 (e.g. based onangle detections). The focus sources may be multiple sound sources (e.g.persons 5, 5′ speaking) prioritised according to the time the hearingaid user 4 spends focusing the head in the direction of the soundsource. The focus sources may be one or more sound sources that thehearing aid user 4 points out manually using a pointer device (notshown, e.g. a remote control device, e.g. implemented as an APP runningon a SmartPhone).

When the hearing aid user 4 turns his head carrying the hearing aiddevices 2, 2′ that determines the rotation as a correlated angle shiftof the tracked sound source(s).

The hearing aid devices 2, 2′ (alone or in combination with anotherdevice, e.g. a remote control, e.g. a SmartPhone, in communication withthe hearing aid devices) individually map (overlapping) parts of thesound scene and exchange information about directions and soundcharacteristics with the other hearing aid devices 2, 2′ (and possiblywith other connected devices). This will allow the other hearing aiddevice 2, 2′ to recognise the sound sources 5, 5′, 5″, 5′″, when theyenter their scope of acoustic view when the hearing aid user 4 isturning his head as illustrated in FIG. 9 b).

The sound scene mapping may be constantly shared between the hearing aiddevices 2, 2′ and other connected devices. The directionality system ineach hearing aid device 2, 2′ may be constantly adjusted in order togive higher loudness to the focus sound sources 5, 5′, 5″, 5″.

The degree of prioritisation of focus sources may be automaticallyadapted according to environmental conditions and personal preferencesettings of the hearing aid user 4.

Free-Fall Indication:

Hearing aid devices 2 are small and expensive. Due to their small sizeand weight, it may not be noticed if the hearing aid device 2 is droppedand the hearing aid device 2 may not be easy to find.

Accordingly, a hearing aid device 2 that is configured to communicatewith a mobile phone (e.g. a SmartPhone) 40 when a hearing aid device 2is falling is a major advantage. The hearing aid device 2 shouldcomprise an accelerometer and/or gyroscope adapted to detect when thehearing aid device 2 is dropped. One possible criterion to determinethat the hearing aid device 2 is dropped may be the detection of anacceleration corresponding to the acceleration of the force of gravityfor a predefined time period e.g. a time period corresponding to thatthe hearing aid device 2 is moved more than 50 cm, e.g. more than 100 cmdownwards in the vertical direction (this depends on the initial speedof the hearing aid device 2).

FIG. 10 a) illustrates a situation where a hearing aid device 2 isdropped by mistake by a hearing aid user 4 that is running. The hearingaid device 2 is provided with a free fall detector that sends a signal35 to a mobile phone 40, e.g. a SmartPhone. The mobile phone 40comprises a GPS device that receives Global Positioning System (GPS)signals to determine the location of the hearing aid device 2 and meansto log the position where the hearing aid device 2 was lost.

Thus, the hearing aid device 2 and the mobile phone 40 constitute analarm system using a free fall detector that is indicating when andwhere the hearing aid device 2 is dropped. Many standard mobile phoneson the market today have a built-in GPS device and means for storing aposition where the GPS device has been used.

FIG. 10 b) illustrates a situation in which a hearing aid device 2 isdropped by a running hearing aid user 4.

The hearing aid device 2 comprises an accelerometer and/or a gyroscopeconfigured to determine the acceleration of the hearing aid device 2.The accelerometer and/or gyroscope constitute a free fall detector thatsends a signal 35 to the other hearing aid device 2′ of a binauralhearing aid system immediately after the hearing aid device 2 isdropped. This alarm signal is provided in the other hearing aid device2′ so that the hearing aid user 4 is warned by an audio signal. By useof wireless communication between the hearing instruments, theacceleration patterns or the free fall detection could be interchanged.Hereby it can be detected if one or both hearing instruments aredropped. Only if one instrument is dropped, a warning in the oppositehearing instrument is necessary.

Accordingly, the hearing aid user 4 is aware that the hearing aid device2 has been lost. The alarm signal may also be also be displayed on themobile phone 40 that the hearing aid user 4 is holding in his left handor sent to a communication device of a caretaker. This may be beneficialfor a caretaker to be noticed on her phone, e.g. if a child has lost ahearing aid device 2.

The hearing aid device 2 may send a signal 35 to the mobile phone 40that may comprise a GPS device so that the position where the hearingaid device 2 was lost can be logged. Hereby, the mobile phone may assistto localise the spot, at which the hearing aid device 2 was lost.Alternatively, the hearing aid device 2 may comprise means for loggingthe last position where a wireless link was established between the twohearing aid devices 2, 2′ or between the lost hearing aid device 2 andthe mobile phone 40.

The hearing aid device 2 according to the disclosure is configured toprovide a warning, which may be triggered even before a wireless link islost, and hereby increasing the probability of noticing when and wherethe hearing aid was lost. An accelerometer and/or gyroscope built-in tothe hearing aid device 2, 2′ can be used to estimate if the hearing aiddevice is dropped (free fall detection).

When the hearing aid device 2 is dropped through the air, a free fall isdetected by the accelerometer and/or gyroscope, and the other hearingaid device 2′ can be alarmed immediately. Furthermore, if the hearingaid user 4 is wearing a GPS device, e.g. a mobile phone with a built-inGPS device, the position of where the hearing aid device was dropped maybe logged in the mobile phone 40, and afterwards be used to assist thehearing aid user 4 in tracking his hearing aid device 2. After a freefall has been detected, and it has been detected that the hearinginstrument has had an impact and is lying without further movement, thehearing instrument can go into a low power mode, where the battery powersolely is used for transmitting a wireless signal with maximum strength,hereby making it easier to localize the hearing instrument. E.g., thehearing instrument could transmit such a localization signal once everysecond in order to prolong the battery time and hereby increasing theprobability of being found.

In one embodiment according to the present disclosure, the mobile phone40 is configured to provide an alarm signal that is sent to an externaldevice (e.g. a mobile phone of a caretaker or a server).

Fear of Losing a Hearing Aid:

It has been indicated that many users of hearing aids have a constantfear of losing it or them. Hearing aids are perceived both as expensiveitems and, by many users also indispensable, thus the fear of losingthem. To address this experienced concern about losing a hearing aid, itis suggested to build in a Drop Alarm feature in hearing aids. The alarmshould be triggered by a free fall and/or a hard landing. For example,it is proposed that once the alarm is activated, some or all of thefollowing actions will be performed:

-   -   The hearing aid will vibrate.    -   The hearing aid will start beeping at a (customized) level        audible to the individual user.    -   A visual indicator on the hearing aid will start blinking.    -   The hearing aid will send a message to the hearing aid in the        other ear.    -   The hearing aid will send a message/e-mail to the user's or        other person's smart phone/tablet/computer.

This will make it easy for the user to identify the location of the losthearing aid. The alarm should e.g. be de-activated by opening andclosing the battery drawer, or by any other activation element (e.g. viaa user interface).

It has also been revealed that even though currently availableinstruction material enables both users and non-users to carry out dailytasks related to handling hearing aids, only very few people know when atask is carried out correctly. As an example, if a relative or a careassistant is to replace batteries in a pair of hearing aids, they get noimmediate indication of whether this has been done correctly or not.Today, a hearing aid typically plays a short jingle when switched on,but most non-users are unaware of this. Furthermore, some non-users whoare aware of the jingle and its function, but are unaware that they needto put the hearing aid close to the ear in order to hear the jingle.Also some users are unaware of the jingle, because they close thebattery drawer before they put on the hearing aids. To address thisshortcoming, we suggest building in a physical indicator, e.g. in theform of a vibrator that will go off for one second each time the hearingaid is switched on. This will let the person changing the battery knowboth that the battery is positioned correctly and that the hearing aidis working.

It is proposed to provide the hearing aid with a drop (free fall)detector and alarm unit that can help the user with their concern oflosing their device. This system may e.g. come with some or all of thefollowing five different features in order to secure diversity:

A. Tactile feature: The hearing aid should preferably have a vibratingdevice incorporated which should be used when the user changes battery,to ensure correct installation of battery. It should also be activatedif the hearing aid falls/lands hard (e.g. if subject to an abruptdeceleration). When the hearing aid falls or lands hard, the hearing aidwill start vibrating. A micro vibration motor (or a similar device) mayform part of the hearing aid to provide the tactile feature. When thebattery is inserted into the battery drawer and locked, the hearing aidis configured to vibrate indicating that the battery is placed correctlyand that the hearing aid is working.

B. Audible feature: The hearing aid should preferably provide differentkinds of alarm notes, e.g. 3 different notes. The alarm notes should beadded automatically according to the user's needs, e.g. by fittingsoftware during a fitting process according to the user's audiogram.This will ensure that users with hearing loss in the high frequent rangewill get alarm notes at lower frequencies. The alarm notes could be atdifferent levels (dB) according to the user's audiogram. When thehearing aid falls/lands hard, it is preferably configured to startbeeping, and/or to issue one or more notes (notifications), preferablyat an audible frequency and dB level for the individual user.

C. Visual feature: The hearing aid should preferably have a visualalarm, i.e. light, e.g. blinking light, when the hearing aid is dropped.This could be featured in a tube of the hearing device (e.g. provided byan optical fiber and an LED) or in that a shell part (e.g. one half ofthe shell, e.g. the one facing the head, when the hearing aid is mountedat an ear of the user, to make it invisible during normal use) istransparent, and then have a diode/LED incorporated in the hearing aidhousing to give light through the transparent shell part.

D. Message feature: The hearing aid should preferably send an alarm toneor message (e.g. “Attention: lost hearing aid”) to the hearing aid in orat the other ear, as soon as it discovers that one hearing aid is infree fall (e.g. “Attention: lost hearing aid”). The other hearing aidcan then, for example, play a downward sweep and/or vibrate.

E. Smart phone/tablet/computer feature: The hearing aid shouldpreferably send a message (e.g. “Attention: lost left hearing aid”, e.g.on a Bluetooth (or Bluetooth Low Energy) or similar, e.g. proprietary,link to another device, e.g. a SmartPhone, e.g. making the devicevibrate, and/or send out an alarm tone. In addition the user couldchoose to have GPS switched on in the hearing aid in order to locate thehearing aid via the other device (e.g. a SmartPhone). This should onlybe provided if the user has given consent to this, because it otherwisecould give the user an unpleasant feeling of being under surveillance.The smart phone would then be able to give information of the locationof the hearing aid, both visually (on a map) and verbally (by a voice inthe phone). The alarm should preferably be set in an off state whenexposed to a free fall or by a hard landing. The fall may preferably bemeasured by an accelerometer.

All together the Drop Alarm will reduce the users' fear of losing theirhearing aids, because if they lose them the Drop Alarm will immediatelyattract the user's attention, so that he/she can find his/her losthearing aid(s).

Shock Surveillance:

The above deals with detecting when and where a hearing aid device isexposed to a fall. The following deals with the ‘impact’ situation whenthe hearing aid device hits the ground after a free fall. In general,not much information on the properties of such impact shocks on hearingaids are available. Most design and validation of hearing aid devicesare based on a number of ‘rules of thumb’ and empirical data. If a largenumber of data on real usage were available (e.g. in a database), thedesign could be optimized with the potential of saving development andtest time as well as pushing the design closer to the limits. Logging ofdata would also allow for self-test in hearing aid devices; if e.g. theyhave been subjected to a predefined number of shocks they can call forservice (e.g. by issuing a beep or a voice message). After a shock hasbeen detected, it is likely that the microphone characteristics havechanged. Hereby the performance of the noise reduction (e.g. including adirectional) system will deteriorate. Thus an automatic microphonematching routine should preferably be run after such a shock has beendetected. This could be done e.g. by increasing the adaptation time ofthe automatic microphone matching system, or it could be done during acalibration of the hearing aid device.

Some or all of the following data could preferably be detected andlogged in a database. The determination of the parameters is based onthe possibility of measuring acceleration in the hearing aid device(s).

Logging the Shock Data:

-   -   Detect all impacts (levels, time and numbers) to the hearing aid        for design improvements.    -   Detect exact impact direction in order to get knowledge for        design improvements.    -   Detect all impacts (levels, time and numbers) to the hearing aid        for improved reliability data.    -   Detect all impacts (levels, time and numbers) to the hearing aid        for improved usage knowledge.    -   Log impact sequence to analyse displacements of        receiver/suspension to improve design.    -   Detect all free falls (fall time, aids direction on impact and        numbers) to the hearing aid for design and reliability        improvements.

Estimating Shock Level:

-   -   2.a As the shock levels can be very high, it can be too high for        the accelerometer to measure. Also the impact will have a very        short duration of time (hence, when a free fall is being        detected, the sample rate and the measurement range of the        accelerometer should preferably be maximized in order to        increase the probability of recording the impact). Instead, the        accelerometer could estimate the drop height by measuring free        fall time and from that estimate the shock level (further the        accelerometer data could possible identify the surface hardness        for use in the estimation).

Reacting to Free Fall or Shock:

-   -   Detect exact impact direction in order to protect the receiver        by displacement of armature in the opposite direction.    -   The IC should be re-booted to avoid that the IC ends up in an        undefined electric state (e.g. due to the creation of glitches        due to the impact, e.g. due to battery contacts being        temporarily disconnected).    -   The feedback path should be estimated again to verify that the        gain margins are still OK.    -   A possible adjustable vent should be set to a default state to        be sure of its position.    -   Best buddy: An alarm warning that something has happened should        be issued (e.g. by the other hearing aid device).    -   Howl, blink, warning should be generated by the hearing aid        device dropped for easy location detection.

Using an Accelerometer for Live Functionality Surveillance:

-   -   An accelerometer can be used to measure vibrations from a        receiver (loudspeaker) to detect changes in vibration pattern        caused by faults in the receiver or other components.

Head Movement:

Four examples are given in the following to introduce a typical setupand relevant parameters and problems involved in measuring movement dataof a hearing aid device or a pair of hearing aid devices located at anear or at both ears, respectively, of a user.

Example 1

How to measure pitch, yaw and roll using a movement sensor:

Pitch, yaw and roll represent angles of rotation around respectiveorthogonal axes of a center of mass of an aircraft. In the following,these terms are used for a head of a user of a hearing aid device or abinaural hearing aid system comprising left and right hearing aiddevices adapted for being located at or in left and right ears of a userrespectively.

A definition of the rotational movement parameters pitch, yaw and rollrelative to the x, y and z axis of an orthogonal coordinate system isillustrated in the left graph of FIG. 11a . Roll is defined as arotation around the x-axis. Pitch is defined as a rotation around they-axis. Yaw is defined as a rotation around the z-axis. Thecorresponding parameters are exemplified relative to a head of a user inthe right graph of FIG. 11 a.

Pitch is defined as a rotation of the head around the x-axis. Can bemeasured by either a single or a pair of hearing aid devices. Agyroscope in a hearing aid device can measure it directly. Measurementsfrom a pair of gyroscopes in each their hearing aid device can beaveraged to provide higher precision. An accelerometer will measure thedirection of the gravity field and the pitch can then be determined bycalculation of the difference between the actual directions of thegravity and a previous determined ‘normal’ direction i.e. theestablished z-axis. If two hearing aids both estimate pitch, they cancombine their results for better precision.

Yaw is defined as a rotation of the head around the y-axis. Can bemeasured by either a single or a pair of hearing aid devices. Agyroscope in a hearing aid device can measure it directly. Measurementsfrom a pair of gyroscopes, one in each hearing aid device can becompared (e.g. averaged) to provide higher precision. With anaccelerometer there are two ways to estimate yaw or more exact angularvelocity ω.

One method uses the centripetal force F=mrω². This is illustrated inFIG. 11b . The radial acceleration a_(y) from an accelerometercorresponds to rω², so we can determine the angular velocity ω as

${\omega = \sqrt{\frac{a_{y}}{r}}},$

where r is the radius either determined physically or estimated. a_(y)is greater or equal to 0 for a rotation but can become less than zero ifcombined with other accelerations. It will be described in the followinghow to isolate the rotational acceleration from a_(y). To avoidimaginary numbers the formula could be changed to

$\omega = {\sqrt{\frac{a_{y}}{r}}.}$

ω on its own does not contain information on direction of rotation. Thisshould be derived from the below integration method.

A second way of estimating the angular velocity ω is based onintegration of the linear acceleration a_(x) orthogonal to the radius ofthe movement as illustrated in FIG. 12a . Angular velocity is defined as

${\frac{d\;\omega}{dt} = \frac{a_{x}}{r}},$

where r is the radius either determined physically or estimated. Solvingfor ω gives:

${\omega = {\frac{1}{r}{\int_{0}^{t}{{a_{x}(t)}dt}}}},$

where r is the radius either determined physically or estimated. Whenperforming a numerical integration, care must be taken to provide a highaccuracy. Instead of the Euler method, Verlet or 4^(th) order RungeKutta should advantageously be considered. This method for finding ω canbe improved, if a pair of hearing aids is present, as the accelerationmeasured could contain a linear movement (like walking) so that theacceleration a_(x) consists of a_(lin)+a_(rot). To remove the linearpart, we can combine the acceleration measured in the same plane on bothsides of the head (see FIG. 12b ). We now have: a1_(x)=a_(lin)+a_(rot)and a2_(x)=a_(lin)−a_(rot), if the point of rotation is centered.Subtracting the two provides:a1_(x)−a2_(x)=(a_(lin)+a_(rot))−(a_(rot))=2a_(rot). Hencea_(rot)=(a1_(x)−a2_(x))/2. The more accurate ω becomes:

${\omega = {\frac{1}{2r}{\int_{0}^{t}{\left( {{a1_{x}(t)} - {a2_{x}(t)}} \right)dt}}}},$

where r is the radius either determined physically or estimated. Thecentripetal method can be improved likewise.

From FIG. 12c the centripetal acceleration a_(cen) can be improved as:a1_(y)=a_(lin)+a_(cen) and a2_(y)=a_(cen)−a_(lin), if the point ofrotation is centered. Adding the two provides:a1_(y)+a2_(y)=(a_(lin)+a_(cen))+(a_(cen)−a_(lin))=2a_(cen), and hence:a_(cen)=(a1_(y)+a2_(y))/2. This also allows a better estimate of thelinear acceleration:a1_(y)−a2_(y)=(a_(lin)+a_(cen))−(a_(cen)−a_(lin))=2a_(lin), and thusa_(lin)=(a1_(y)−a2_(y))/2

Roll is defined as a rotation around the x-axis. Roll can be determinedas yaw but using acceleration in the z-plane instead of the x-plane. Butadditionally, the gravity method used for ‘Pitch’ can also be appliedhere.

Example 2

This example deals with achieving a higher accuracy for linear headmovement estimates using two or more accelerometers. If the accelerationmeasured in the same geometric plane by a pair or more accelerometersare averaged, the precision increases and unwanted rotationalinformation can be removed. The example shown in FIG. 12b becomes:a1_(x)=a_(lin)+a_(rot) and a2_(x)=a_(lin)−a_(rot), if the point ofrotation is centered. Adding the two provides:a1_(x)+a2_(x)=(a_(lin)+a_(rot))+(a_(rot))=2a_(lin), and hence:a_(lin)=(a1_(x)+a2_(x))/2. Further, the precision is improved by 3 dB.

Example 3

This example deals with estimating the distance between the hearingaids. If at least one accelerometer and one gyroscope are present(either in one hearing aid or in a pair), it is possible to estimate thedistance from the center of rotation to the sensors. The gyroscope willprovide the angular velocity ω_(g) and the accelerometer providesa_(a)=rω_(g) ². Solving for radius r gives:

$r - {\frac{a_{a}}{\omega_{g}^{2}}.}$

Assuming mat me center or rotation is following a normal distribution itis possible to estimate the radius and so the distance between thehearing aids (2×radius) by averaging a large number of radius values r.

Example 4

This example deals with overall necessary conditions when using sensorsdistributed in more devices as for example a pair of hearing aids whereit is necessary to be able to exchange and analyze the data. The linksbetween the devices are preferable wireless, but can also be establishedvia wired connections. The data must be synchronized in time between thedevices to ensure that the data to be analyzed are aligned in time. Theanalysis can take place in each device, in one device that transmits theresult to the other devices, or distributed over more devices. In theabove examples 1, 2 and 3, it has been assumed that the center ofrotation is located on an imaginary line drawn between a pair of hearingaids. In reality we suspect that the center of rotation ‘O’ is placedoff-line as indicated in FIG. 13. This means that the estimate ofangular velocity ω is less accurate using integration of acceleration ifno correction is applied. The gravity and the centripetal method arestill correct even with ‘O’ off-line.

On/Off Detection:

Hearing aid device users often forget to turn their hearing instrumentsoff and then the limited battery power is wasted. Especiallyrechargeable batteries have limited battery life. Users that havereduced dexterity and eye sight, find it difficult to turn on hearinginstruments, with small buttons and battery drawers. Finally the hearinginstrument can start hauling during insertion into the ear canal, if thegain is on before it is placed on/in the ear. There is thus a need foran ‘intelligent’ on-off mechanism for hearing aid devices.

A movement detector (e.g. an accelerometer) built into the hearinginstrument is able to detect if the hearing aid device is being movedand how it is moved (fast/slow, up/down, etc.). In a simple use case,this can be used to detect that the user has taken the hearinginstrument out and left it on a table and the hearing instrument can beconfigured to automatically turn off or be put into a ‘low-power’ or‘sleep mode’, where the power consumption is minimal. When the userpicks up the hearing instrument (e.g. the next morning), as detected bythe movement sensor, it is automatically turned on, e.g. in a ‘standbymode’, and when it is placed into the ear, the gain is automaticallyturned on.

The detection using the accelerometer can be combined with a range ofdifferent detections for better and more reliable ‘on-ear-detection’.Other detections could be:

-   -   Temperature detection—    -   Wireless range between hearing instruments.    -   Acoustical feedback path estimation to detect, if the hearing        instrument is located in the ear (as opposed to on a table,        e.g.).    -   Own voice detection.    -   Heart pulse detection

All this can contribute to a longer battery life and easier operation ofthe hearing instrument.

The first suggested version of the disclosure (system A) is mainly basedon the accelerometer itself, combined with a timer. See FIG. 14a andsections A1, A2, A3, A4 below.

A1. When the battery is placed in the hearing instrument, the hearinginstrument is configured to start up in a standby mode where the powerconsumption is minimal. In a full automatic version, the accelerometeris used to detect that the hearing instrument is placed on the ear andthen power up fully with full gain. The following three detections couldpreferably to be present:

-   -   Movement: The hearing instrument is not lying still.    -   Angle: The angle of the hearing instrument is close to the angle        it is expected to have when operationally mounted on the ear.        (This could be detected binaurally for more reliable detection)    -   Time: Detection of movement and angle have been present for a        minimum amount of time, e.g. 5 seconds.

A2. In an alternative version where full automatic hearing instrument isnot desired, the hearing instrument can be woken up by tapping thehearing instrument with the fingers. This is detected by theaccelerometer of the hearing instrument, which is powered up and fullgain applied.

A3. To detect that the hearing instrument is taken off and put on atable, the following detections are preferably present:

-   -   Movement: The hearing instrument is lying still.    -   Time: It has been lying still for a minimum amount of time, e.g.        30 sec.

A4. The battery is taken out, and the hearing instrument is completelypowered off.

In the next suggested version of the disclosure (system B) theaccelerometer detection is combined with other detections. See FIG. 14band sections B1, B2, B3, B4 below.

B1. When the battery is placed in the hearing instrument, the hearinginstrument is configured to start up in a ‘standby mode’, where thepower consumption is minimal.

B2. In the full automatic version, the movement sensor (e.g. anaccelerometer) is used to detect that the hearing instrument is placedon the ear and then configured to power up fully with full gain. Thefollowing three or four detections could preferably be present:

-   -   Movement: The hearing instrument is not lying still.    -   Angle: The angle of the hearing instrument is close to the angle        it is expected to have when operationally mounted on the ear    -   Time: Detection of movement and angle has been present for a        minimum amount of time, e.g. 10 seconds.    -   DFC (Dynamic Feedback Cancellation): If the expected detection        of movement, angle and time is present, then the hearing        instrument will play an acoustical signal out of the speaker,        and use the DFC system (incl. a feedback path estimation system)        to detect the feedback path. If the feedback path is close to        the expected feedback path for the hearing instrument user, then        the hearing instrument is fully powered up

In case acceleration patterns from both hearing instruments areavailable and interchanged binaurally and correlated, it is a verystrong indication that both hearing instruments are located on bothears.

B3. To detect that the hearing instrument is taken off and put on atable, the following detections are preferably present:

-   -   Movement: The hearing instrument is lying still.    -   DFC: DFC has detected that the hearing instrument is out of the        ear (e.g. by howling/larger than normal feedback path estimate).    -   Time: The movement and DFC detections have been present for a        minimum amount of time, e.g. 30 sec.

B4. The battery is taken out, and the hearing instrument is completelypowered off.

Additional details of the on-/off-detection (and switching) usingmovement sensor(s):

-   -   The accelerometers can work independently from the general        signal processing unit (DSP) of the hearing aid device, and be        used to control a switch to power up the DSP, for further signal        processing, e.g. necessary for determining a microphone        direction (angle of inclination) of the haring instrument, the        feedback path estimate (DFC), etc.    -   The accelerometer can have a built-in temperature sensor, a        ‘tapping detector’ and ‘lying flat detector’ (the latter two        detectors being e.g. implemented using an accelerometer).    -   The power consumption of the movement sensor (e.g.        accelerometer) can be as low as in the range from 1 μA to 130        μA. The hearing instrument can be running in a suspend mode        where the total current consumption can be lowered to around 600        μA, which is around half the current consumption from a normal        power on mode. For a standard hearing aid with a 175 mAh, 1.2 V        battery with 16 hours of daily use, the battery life would be        extended for at least one more day compared to if the hearing        aid is on 24 hours a day.    -   In a design with rechargeable batteries where the battery does        not need to be replaced by the end user, it is possible to make        a design with no buttons for easier use, and a sealed housing        for better reliability.    -   The in-ear detection can also be detected (alone or in        combination with other detections), by detecting the users        pulse, by measuring the change in acceleration caused by the        heart rate pulse.

The in-ear detection can also be combined with the own voice detectionfor a more reliable detection.

LIST OF REFERENCE NUMERALS

-   -   2, 2′—Hearing aid device    -   4, 4′—Hearing aid user    -   5, 5′, 5″, 5′″—Individual    -   6—Ear    -   8—Sensor member    -   10—Ear mould    -   12—Tube    -   14—Time    -   16—Level of physical activity    -   18—Histogram    -   20—Hearing aid settings    -   22—Level of physical activity    -   24, 26, 28, 30—Parameter    -   32—Loudspeaker    -   34—Sound    -   35—Signal    -   36—Mouth    -   38, 38′—Microphone    -   40—Mobile phone    -   42, 44—Component    -   46—Actuator    -   48, 48′—Coil    -   g—Gravity    -   d₁, d′₁, d₂, d′₂—Distance    -   α, φ—Angle    -   acc—Acceleration    -   H—Horizontal    -   H_(s)—Line    -   I—First position    -   II—Second position    -   III—First position    -   IV—Second position    -   P₁, P₂—Setting

1. A hearing aid device for improving, augmenting and/or protecting thehearing capability of a user when receiving acoustic signals from thesurroundings of the user, the hearing aid device comprising an inputunit for generating corresponding audio signals, a signal processingunit for modifying the audio signals, an output unit for providingmodified audio signals as audible signals to at least one of the user'sears, antenna and transceiver circuitry for establishing a communicationlink to another hearing aid device, and thereby allowing the exchange ofinformation between them, a sensor member for detecting the movementand/or acceleration and/or orientation and/or position of the hearingaid device, where the sensor member comprising an accelerometer capableof determining the acceleration acc in the hearing aid device and tocompare a direction of detected acceleration vector acc to a directionof gravity g, and a free fall detector for detecting when and where thehearing aid device is dropped in free fall, the free fall detectorcomprising the accelerometer, where the hearing aid device is configuredto send a signal to the other hearing aid device when free fall isdetected by the free fall detector.
 2. A hearing aid device according toclaim 1, wherein the hearing aid device is configured to send the signalto the other hearing aid device by the antenna and transceivercircuitry.
 3. A hearing aid device according to claim 1, wherein thehearing aid device is configured to send the signal to an auxiliarydevice when free fall is indicated by the free fall detector.
 4. Ahearing aid device according to claim 1, wherein free fall detectordetects the hearing aid device is dropped when detecting an accelerationof the hearing aid device corresponding to the acceleration of the forceof gravity for a predefined time period.
 5. A hearing aid deviceaccording to claim 1, wherein, after the free fall detector detects freefall of the hearing aid device, the hearing aid device is configured toswitch into a low power mode, and transmit a wireless signal withmaximum strength.
 6. A hearing aid device according to claim 3, whereinthe auxiliary device comprises a mobile phone.
 7. A hearing aid deviceaccording to claim 1, wherein the hearing aid device is configured fordetecting if the hearing aid user is moving or turning the head and forimproving and/or augmenting received acoustic signals from thesurroundings of the hearing aid user by compensating for the headmovement if it is detected that the hearing aid user is moving orturning the head.
 8. A hearing aid device according to claim 2, whereinthe sensor member is configured to control the signal processing unit toallow determining a microphone direction or angle of inclination of thehearing aid device.
 9. A hearing aid device according to claim 1configured to use the sensor member together with other sensors todetect whether or not the hearing aid device is located at or on one ofthe ears of a user.
 10. A hearing aid device according to claim 1configured to use the sensor member to detect if the hearing aid deviceis being moved and to characterize the movement, and wherein the hearingaid device is configured to be automatically turned on in a fullpower-on mode or in a ‘standby mode’, when the sensor member detectsthat the hearing aid device is in a ‘movement mode’.
 11. A hearing aiddevice according to claim 10 configured to characterize the movement inone or more of fast/slow, and up/down.
 12. A hearing aid systemcomprising two hearing aid devices according to claim 1; and anauxiliary device, and wherein the hearing aid system is configured toallow the hearing aid devices and the auxiliary device to communicatewith each other.
 13. A hearing aid system according to claim 12, whereinthe hearing aid system is configured to log the position where free fallis detected by a free fall detector of at least one of the two hearingaid devices.
 14. A hearing aid system according to claim 12, wherein thehearing aid device(s) comprise(s) means for wirelessly logging thelocation of the hearing aid device on the auxiliary device.
 15. Ahearing aid system according to claim 12, wherein the auxiliary devicecomprises a GPS device.
 16. A hearing aid system according to claim 12,wherein the auxiliary device is configured to log the position at whicha free fall is detected by the free fall detector.
 17. A hearing aidsystem according to claim 12, wherein the auxiliary device comprises amobile phone.